This is how it all went down:
In the 3 years that I lived happily with my bike, only 2 times it refused to start. I presumed it was due to the cold, affecting the battery. After a couple of days the problem disappeared on it's own, and the bike started again in both cases.
I visited an authorised Aprilia service where I was told that it's the fuel pump that it's starting to fail.
To add to my dismay, Aprilia doesn't sell just the fuel pump as a replacement part, but the whole assembly including the fuel gauge sensor, and the fuel filter. How much does it cost you ask? £433 (519 euros) !!!
And this is just the cost of the part. You also have to add the cost of labour to disassemble half the bike to reach inside the tank.
So I postponed it. The mechanic told me that a well-placed punch on the left side of the tank where the fuel pump is located, will make it run again. And so I did. Every time the bike refused to start, I would punch it once, and it would always start. On some rare occasions I had to punch 3 or 4 times, but the trick would always work. And so 1 year passed, and I got used to all the punching.
Until it stopped working completely. No matter how hard I slapped the tank, the engine wouldn't start. After 38.800km of The fuel pump went from living-dead to just dead.
It was about time to hack it. There's no way I would pay 500+ euros for a fuel pump that allegedly has the tendency to fail again and again, each time setting you back 500 euros.
Fortunately many people around the world suffer from the same problem, and thanks to the power of internet they share some of their knowledge and lessons taught. In this case google is our friend. I found invaluable help in the ApriliaBikers.gr forum, and the ApriliaForum.com.
The main idea is that instead of buying the whole assembly from aprilia, you replace just the faulty pump with a car fuel pump. The problem is that there is no fuel pump on the market small enough to fit in the place of the original one so you have to be creative. Generally any pump will do as long as it's 12v and has a rated pressure above 3.2 bar. So I went out there and asked around at the car-parts shops. Some were persistent to know the make and model of the car it's going in, and as soon as I said the word motorcycle they wouldn't listen any more. In the end I found a helpful shop owner who gave me a Siemens 3.8 bar pump that looked small enough. Cost: 60 euros.
Then I searched for a suitable in-tank fuel filter. According to the good people of the aforementioned forums, the Mann MWK-44 is a perfect replacement. It's better build than the original Aprilia, and even cheaper: 48 euros for the aprilia, and just 22 for the Mann.
If you want to buy the same pump as me you might want to use the markings on the box:
It reads 993-784-025X Kraftstoffpumpe HPi8
Before you start the operation make sure you've got all the ingredients:
- 3.8 Bar 12v Fuel Pump
- Mann MWK-44 Fuel Filter
- 50cm of hose
- 4 hose clamps
- Hex keys collection
- 7mm Wrench / spanner
My brother demonstrating the items of the utmost importance. A new pump and a cup of coffee. (The Greek frappe kind).
It's very handy to have a brother to help you. Couldn't have done it without him. Thanks bro!
In order to get to the fuel pump you need to remove the tank. In order to get to the tank you need to remove the headlight and the glove-box compartment. Here we go: Start unscrewing!
Unscrew 6 screws to separate the dash from the headlight.
Unscrew the supporting bracket, and disconnect the cabling from the bracket.
The head of the beast.
Unscrew the glove-box but leave the latch mechanism as is. It doesn't bother us.
With the glove-box and the 2 side-covers removed, lifting the tank is pretty straight forward. Just make sure to unscrew the central bolt under the glove-box and 2 on the side. I'm sorry for the lack of photos but we got carried-away on this point.
The striped-down bike, and my bro complaining about the low level of coffee.
This is where the fuel pump assembly came from
The golden part in there is the original faulty pump. It will be replaced by the brand new siemens on the right.
The original and the replacement side by side
There's no way it will fit without some "modifications"
I had to "surgically" remove all of the pump holder (Click to enlarge)
The final result. Beautiful.
In my case the DC connectors where slightly different so I had to solder some new ones.
This is the complete assembly before I dip it back into the tank
Put it back there.
Re-assemble, and hopefully it will run.
Once you turn the key and before you hit the ignition, you should hear the pump working.
In my case I could hear the pump working, but once I hit the ignition it wouldn't start.
Turns out I had soldered the terminals the wrong way and the pump worked all right, but instead of pumping fuel into the engine it would suck it out. We removed it once again, soldered positive to positive and ground to ground, put it back in, and it started at once!!
Total cost of the project 89 euros. I saved about 430 euros